In the mining and construction industries, loading and moving of heavy materials such as sand, gravel and rock is often accomplished using heavy machinery such as scoop trams, front-end loaders and powered bucket digging devices. During operation, these buckets tend to wear along their leading and side edges due to abrasion when entering the material pile and during contact with the ground. During use, the leading or lip edges and side edges may tend to wear down, sometimes very quickly. After the lip edges and side edges wear down to a point where the base plate or bucket are threatened with wear, the bucket may typically be removed and sent to be refurbished by replacing the lips or lip edges and side edges. Bucket removal is a relatively common practice in the mining industry at present. Rework and replacement of bucket lips and side edges can be a major undertaking involving burning, cutting and welding. Time may be lost if the loader is transported to a shop where the bucket is to be replaced. In a mining setting, the loader may remain inside the mine, the bucket being cut into two pieces and transported out of the mine to the surface. The replacement bucket may be returned in two pieces and be welded together before being placed on the loader. If a replacement bucket is not available or the replacement process is too cumbersome at the time, an operator may continue operating the loader nonetheless. As a result the base plate or the bucket itself may be damaged through overuse and may then require much more extensive repair than would otherwise be expected. The replacement of the base plate or bucket may well be much more costly than the continued use gained by operating the loader for the extra time.
Alternatively, the mine may keep an inventory of repaired buckets available. It is advantageous to reduce the ratio of buckets in inventory to the number of buckets in use, since buckets held in inventory, or being refurbished, are capital assets that are not earning revenue. Thus, it is advantageous to facilitate relatively simple replacement of wear plates and teeth in the mine, and to reduce the number of major overhauls requiring bucket removal to the surface.
When a loader or underground scoop tram is used for loading or transporting materials it is common to weld a base plate to the lower front edge of the bucket, the welding join line running from side to side across the bucket. The bucket is usually made of mild steel and the base plate is made of a mild steel or high carbon steel. The base plate is sometimes of greater thickness than the bucket plate. The upper surface of the base plate is installed flush with the inner surface of the bucket. The base plate has a lead, provided by leading edges that extend forwardly at an angle from the lower corners of the bucket to converge at a central point or tip. Different leads are selected by different operators to suit specific conditions. It is common for base plates to have leads of six, eight, ten or twelve inches, the lead being the distance that the tip is located forwardly of a line joining the outside corners of the bucket. A number of known scoop tram buckets have widths in the range of 56 to 112 inches, the tangent of the angle of the lead, viewed from above, being the lead dimension divided by the half width of the bucket.
The supply of replaceable wear edge parts and plates for the aforementioned wear areas, namely the forward lips and side edges and adjacent wing leading edges and sides of excavating or loader buckets, or similar, is the subject of this application; as well as a system of standardization that includes the supply and installation of universal, removable, and replaceable, wing, lip, and side edge wear segments.
Loader buckets currently come in a variety of sizes. The present supplies of lip and side edge wear components, to meet the numerous different bucket leads, involve producing and stocking a wide variety of wear segments. As a result, many different sizes of lips and side edges may be manufactured and stocked to meet demand. This results in a need to maintain a relatively large inventory.
Replaceable and weldable, leading edge wear shroud kits have been used in the past, but have tended to include elements as much as 40 inches wide or more. Such a part may weigh three hundred pounds or more. In general, the greater the weight of the part, the more difficult it is to handle, whether by hand or by machine, whether in shipping, transferring from one form of transport to another, installation and/or removal.
In addition, the mating faces of the aforementioned parts may not be planar, and may not be aligned with the forward and rearward direction of the bucket. Where the mating interfaces are arcuate, curved, or splayed, it may not be possible to remove each part without first removing another neighboring part. The other part may not require replacement. This may complicate the occasional replacement of a single broken part, and may make general replacement of wear segments more time consuming than it need be. It would be advantageous to tend to avoid this complication by making the sides of adjoining segments straight and aligned, and preferably generally running in the fore-and-aft direction, to permit a segment to be slid into place between its neighbors. Although larger segments can be used, it would be advantageous to employ plates or segments that are in the range of 3 inches to 12 inches wide, and 6 inches to 6 feet long. Similarly, it would be advantageous to keep the weight of each wear segment, or as many of them as practicable, below about 80 lbs., and preferably below about 50 lbs. It would also be preferable to be able to remove any individual plate or segment without having to remove others first. That is, it would be advantageous to employ wear plates or segments that do not require a specific order of removal and installation.
It would be a further advantage, to adopt a wear plate or wear bar system involving relatively few components, and relatively simple installation methods such as may be made in place (i.e. on site) with only minor lifting devices and readily available welding tools (i.e. oxy-acetylene torches). Another option is to sell one size, or a relatively small number of sizes, of wear plates or bars that can be trimmed or cut by the user in the field to match the bucket size. In this manner, the wear parts or bars can be sold like lumber and cut to size at the job site.
The effectiveness of a loader is determined by the number of loads per hour that can be loaded for a given material. Currently, lips and side edges for attachment to base plates have wedge shaped or rectangular profiles. These profiles may not be conducive to easy rolling of muck or other materials into the bucket. As a result, the effectiveness of the loader is reduced as muck gets caught on the lips and side edges or if the muck is slow to roll off the lips and side edges into the bucket. It may be advantageous to have lips and side edges with profiles that tend to encourage rolling motion in the muck. It may also be advantageous to have a side edge profile in which accumulation of muck or other materials is deterred, or where accumulation is directed to certain areas.
It would be advantageous to be able to trim or cut a cast or forged part to a customizable size for installation in the field. It would also be advantageous if the shape and profile of the side edges were designed to encourage a rolling action in the material to be loaded and to minimize wear/abrasion to the wear part. It would also be advantageous to use a method for providing lips and side edges which reduces inventory variety and inventory costs while still supporting a wide variety of bucket widths and side edge configurations.
Accordingly, there is a need for new lips and side edges (i.e. front and sides) wear parts and a new method for providing and mounting such lip and side edge wear parts, and other wear parts.